2011-03-14_REPORT - C1982056 (3)

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Longwall mining was completed in the EMD by early-January 2001. Production from the NMD, 12 Rt Longwall S Panel, was underway by late January 2001. The EMD was permanently sealed in October 2001 removing all access to the 6 Rt and 7 Rt gate roads. Thus, no measurements are available in this area for 2006. Historical data is available in previous AHRs. The last flows measured for 2000 showed seasonal variations, with an average annual flow of approximately 65 gpm. The EMD was monitored periodically at the TORT well shaft during 2010. Northern Mining District (NMD): At the time of the 2010 inflow study, the mine operation had completed the 23 Rt panel. During 2009, the main sources of water came from the two most recent shafts in the 6MN area, and two fault crossings. Total inflow is estimated to be on the order of 80 gpm. Inflows continued in the Northeast Submains, although there appears to be a continued decrease in ceiling dripping. The highest inflows were about 20 gpm for the new 6MN shaft, and about 15 gpm from a floor sump at inflow site 8 (IF8) with a conductivity of 2270 (Trout Creek Water). This may have been impacted by the addition of roof drip collection to the sump system. The next highest inflow was at raise bore area (IF 38 and IF 37), which was on the order of 10-gpm (down from an estimated 20 gpm in 2005), Field conductivity measurements were about 1500 umhos/cm. This site is a blend of Wadge and Twentymile Sandstone water. Inflow at the remaining sites (primarily roof drippers) were either dry or significantly lower, often less than a gallon per minute. New Western Mining District (WMD): The 2010 inspection along the newly completed 17LT and 18LT gate roads indicated estimated inflows of 15 to 20 gpm. The majority of sites were modest roof drippers, with sites 55 and 57 exhibiting the highest flows, both on the order of 2 to 3 gpm. The majority of the drippers seen in 2009, 0 had dried up. 3.9 Water Balance In early 2009, TCC conducted a water balance study to better access water use and allocations for mine operations, as well as mine dewatering. A flow chart was provided in the 2009 AHR, illustrating water movement for the mine in early 2009. Note that there have been some changes in flow patterns since this study. Another mine water balance is anticipated to be performed in 2011, which would be reflected in the 2011 AHR. 4.0 SUBSIDENCE IMPACTS No significant subsidence impacts occurred to local creeks in 2010. Some historic information follows. During the second-half of 2008, mining included the 22RT panel and the start of the 23RT panel. Water quality data was collected from established sites along Fish Creek in areas underlain by gate-roads or longwall panels in previous years. In 2008 there was no active mining beneath. Fish Creek, and therefore no additional subsidence beneath Fish Creek.. No structures were undermined during the period, and thus no adverse impacts were evident (For additional detail, review previous Subsidence Survey Reports, submitted to DRMS). Fish Creek: Historically, hydrologic monitoring of potential subsidence impacts from the earlier 17 and 18 - Right Panels utilizes four alluvial wells and four nearby surface sites. These sites are shown on the attached First Half 2008 Subsidence Map. These include alluvial well AVF-14 and associated surface site SW-14 (upstream of 17-Right subsidence zone). Also utilized are alluvial well 008-AU3 and associated surface Site 305 (downstream 17